Threshold needed before starting to generate position changed events

This applies to all QML elements that handle mouse events (e.g. Flickable, MouseArea, ListView etc).

Trying to tap/long-press an item in e.g. a Flickable easily cause the view to unintentionally wiggle.
To avoid this, a small movement threshold (e.g. 10-20px, perhaps depending on physical screen size?)
needs to be added (no position changed events should be generated before exceeding the movement
threshold).